import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * 输入一个字符串，求出该字符串包含的字符集合，按照字母输入的顺序输出
 * 1 <= n <= 100
 * 多组输入
 * User: xwl
 */
public class Test1 {
    // main
    public static void main(String[] args) {
        // 多组输入
        Scanner scan = new Scanner(System.in);
        while (scan.hasNextLine()) {
            String str = scan.nextLine();
            String ret = func(str);
            System.out.println(ret);
        }
    }

    // 判断
    public static String func(String str) {
        // 建一个映射空间
        boolean[] flg = new boolean[52];
        StringBuilder stringBuilder = new StringBuilder();
        // 实现
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (flg[ch] == false) {
                stringBuilder.append(ch);
                flg[ch] = true;
            }
        }
        return stringBuilder.toString();

    }
}
